Developing high activity and low-cost materials to produce hydrogen by the sustainable way of photoelectrochemical is key to social development.The abundance and inexpensive Cu_(2)O has been received increasing resear...Developing high activity and low-cost materials to produce hydrogen by the sustainable way of photoelectrochemical is key to social development.The abundance and inexpensive Cu_(2)O has been received increasing research as its suitable energy level for photocatalytic water reduction.However,the fast charge recombination rate and the sluggish catalytic kinetics are the huge challenges facing the Cu_(2)O photoreduction.Here,the highly reactive Cu_(2)O@C-MoS_(2)photocathode is constructed by depositing dual-cocatalysts of the carbon layer and MoS_(2)nanosheets on Cu_(2)O nanowires to realize efficient water reduction.An impressive carrier concentration of 6.59×10^(23)cm^(-3)is received,which is 2.78 times of the bare Cu_(2)O,resulting in remarkable enhancement in photocurrent density of 3.34 times for the Cu_(2)O@CMoS_(2)photocathode.Moreover,the applied bias photon-to-current conversion efficiency of the bare Cu_(2)O enhanced 4.5 times from 0.16%to 0.72%in the Cu_(2)O@C-MoS_(2)photocathode.The analysis shows that the Cu_(2)O as light absorber,the carbon layer as electron transfer promoter,and MoS_(2)nanosheets as catalytic sites,thus facilitating chrage separation and enhancing catalytic kinetics.This system paves a feasible strategy for designing other photoelectrodes to realize efficient charge separation and high catalytic activity.展开更多
In the process of oilfield development, oilfield dewatering project has always been a big problem for oilfield developers. Because the original oilfield development technology uses a single well, the efficiency of the...In the process of oilfield development, oilfield dewatering project has always been a big problem for oilfield developers. Because the original oilfield development technology uses a single well, the efficiency of the single well is very low, which results in the deterioration of the effect in the development process of many oilfields and the loss in oilfield development. Therefore, in order to improve the benefit of oilfield development and the effect of water flooding development, this paper makes an in-depth study on the water-stable and oil-efficient development of high-water-cut and later-stage complex fault-block oilfields.展开更多
The rational design of a heterostructural photocatalysts with efficient charge separation and accelerated interfacial charge transfer holds great promise for boosting photocatalytic activity.Herein,we have developed a...The rational design of a heterostructural photocatalysts with efficient charge separation and accelerated interfacial charge transfer holds great promise for boosting photocatalytic activity.Herein,we have developed a unique hierarchical In_(4/3)P_(2)S_(6)/TiO_(2) heterojunction with P-O interfacial bonding for photocatalytic water reduction.By integrating emerging In_(4/3)P_(2)S_(6) nanosheets through intense interfacial coupling effect,the optimized In_(4/3)P_(2)S_(6)/TiO_(2) heterostructure exhibits a remarkably enhanced photocatalytic H2 evolution activity compared to that of pristine TiO_(2).Combined experimental and theoretical results confirm that multiple interfacial bonded step-scheme(S-scheme)charge transfer pathways are established in the In_(4/3)P_(2)S_(6)/TiO_(2) photocatalyst,which synergistically promote charge separation and transfer through the robust interfacial electric field and rapid charge migration pathways formed by interfacial bonds.This study emphasizes the significance of developing novel interfacial bonded In_(4/3)P_(2)S_(6)-based S-scheme heterostructures,paving a new strategy towards enhancing photocatalytic activity for H_(2) evolution.展开更多
Photocatalytic water splitting and carbon dioxide reduction provide us clean and sustainable energy resources. The carbon dioxide reduction is also the redemption of the greenhouse effect. MoS/TiOphotocatalysts based ...Photocatalytic water splitting and carbon dioxide reduction provide us clean and sustainable energy resources. The carbon dioxide reduction is also the redemption of the greenhouse effect. MoS/TiOphotocatalysts based on TiOnanoplates have been synthesized via a hydrothermal acidification route for water and carbon dioxide reduction reactions. This facile approach generates well dispersed Mo S3 with low crystallinity on the surface of TiOnanoplates. The as-synthesized MoS/TiOphotocatalyst showed considerable activity for both water reduction and carbon dioxide reduction. The thermal treatment effects of TiO, the loading percentage of MoSand the crystalline phase of TiOhave been investigated towards the photocatalytic performance. TiOnanoplate synthesized through hydrothermal reaction with the presence of HF acid is an ideal semiconductor material for the loading of MoSfor photocatalytic water and carbon dioxide reduction simultaneously in EDTA sacrificial solution.展开更多
Drinking water loss or Non-Revenue Water (NRW) threatens the financial viability of water utilities and sustainable natural water resource management. However, little attention has been paid to quantitative assessment...Drinking water loss or Non-Revenue Water (NRW) threatens the financial viability of water utilities and sustainable natural water resource management. However, little attention has been paid to quantitative assessment of the spatial distribution of water losses in Rwanda. Therefore, this study focused on the magnitude of water losses, the associated environmental and socio-economic consequences, as well as the potential benefits from water loss reduction in Rwanda. Based on water usage records from the Water and Sanitation Corporation (WASAC) of Rwanda, NRW was calculated for 15 WASAC branches and Provinces, from July 2013 to June 2014, by using the International Water Association (IWA) standard water balance approach. The results highlight an annual NRW of 16,502,198 or 41% of the total water produced, inducing a revenue loss of US$ 8,713,156. In 14 of the 15 WASAC water branches and all Rwandan provinces, the NRW ratios exceed the NRW threshold (10%) recommended by the American Water Works Association (AWWA). Because of the lost revenue, the water facilities may not expand quickly enough to meet the demands of the rapidly growing population. The suggested 50% reduction in NRW would provide additional 8,251,100 m<sup>3</sup> of treated water yearly, enough to serve extra 41,925 households or irrigate 661 ha of cropland and save US$ 4,356,579, which would reduce the financial gap in Rwanda’s National Water Improvement Project by more than 24%.展开更多
La/Zr co-doped SrTaO_(2)N has been investigated as visible-light-active photocatalysts for water reduction.Unlike previous aliovalent doping that leads to a decrease in light absorption,La/Zr co-doping largely preserv...La/Zr co-doped SrTaO_(2)N has been investigated as visible-light-active photocatalysts for water reduction.Unlike previous aliovalent doping that leads to a decrease in light absorption,La/Zr co-doping largely preserves the visible light absorption of SrTaO_(2)N.More importantly,the La/Zr co-doping not only helps to improve surface hydrophilicity and reduce particle sizes but also effectively inhibits defect formation(e.g.Ta^(4+))in SrTaO_(2)N.These modifications are responsible for significant enhancements in photocatalytic H_(2)production.AQE as high as 0.84%was achieved at 420±20 nm for Sr_(0.4)La_(0.6)Ta_(0.4)Zr_(0.6)O_(2)N(x=0.6),which also showed good durability and stability.Further analysis suggests that La/Zr co-doping negatively shifts the conduction band edge positions of SrTaO_(2)N and contributes to better charge separation conditions.展开更多
Grafting a WVI–(OH)_(2) functionality on the surface of polyoxometalates (POMs) makes the concerned POM compounds,Na_(6)[{CoⅡ(H_(2)O)_(3)}_(2){WVI(OH)_(2)}_(2){(BiⅢWVI_(9)O_(3)_(3))_(2)}]·8H_(2)O (1) and Na_(4...Grafting a WVI–(OH)_(2) functionality on the surface of polyoxometalates (POMs) makes the concerned POM compounds,Na_(6)[{CoⅡ(H_(2)O)_(3)}_(2){WVI(OH)_(2)}_(2){(BiⅢWVI_(9)O_(3)_(3))_(2)}]·8H_(2)O (1) and Na_(4)(Himi)_(2)[{MnⅡ(H_(2)O)_(3)}_(2){WVI(OH)_(2)}_(2){(BiⅢWVI_(9)O_(3)_(3))_(2)}]·28H_(2)O (2) prominent heterogeneous electrocatalysts for water reduction to molecular hydrogen. We have identified that the WVI–(OH)_(2) functionality acts as the active site for electrocatalytic hydrogen evolution reaction (HER). The chances of in situ generation and participation of secondary species (metal nanoparticles etc.) in the present electrocatalysis have been eliminated by performing controlled experiments. The electrocatalysts 1 and 2 are stable enough towards HER up to 1000 cycles of cyclic voltammetric measurement and 10 hours chronoamperometry. The relevant turnover frequencies of 1 and 2 are 0.593 s^(-1) and 0.634 s^(-1) respectively exhibiting high efficiency towards electrocatalytic HER. This work has potential to generalize that POMs having M–OH functionality attached on its cluster surface would function as catalysts for HER.展开更多
Herein,we disclosed the g-C_(3)N_(4)/LaFeO_(3) nanocomposite photocatalyst,a mediator-free direct Z-scheme photocatalytic system,prepared using a mechanical mixing method with reliable interfacial interactions. The na...Herein,we disclosed the g-C_(3)N_(4)/LaFeO_(3) nanocomposite photocatalyst,a mediator-free direct Z-scheme photocatalytic system,prepared using a mechanical mixing method with reliable interfacial interactions. The nanocomposite formation was determined by X-ray diffraction (XRD),transmission electron microscopy (TEM),and X-ray photoelectron spectroscopy (XPS). The optical properties of the nanohybrids were also characterized using UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The results clearly indicated that the g-C_(3)N_(4)/LaFeO_(3) nanocomposite was effectively fabricated,with reliable interfacial interactions and a good heterojunction interaction between g-C_(3)N_(4) and LaFeO_(3),which can considerably enhance the photocatalytic activity as compared to pristine g-C_(3)N_(4) and LaFeO_(3). The high HER (1152 μmol h^(−1) g^(−1)) was also confirmed by the PL spectra,Mott–Schottky plot,electrochemical impedance spectroscopy (EIS),and solid–solid interfacial interactions.展开更多
Energy-efficient electrolytic hydrogen generation is highly desired but still remains challenging.In this work,we demonstrate that a Cu_(3)P nanoarray on copper foam(Cu_(3)P/CF)behaves as a high-performance electrocat...Energy-efficient electrolytic hydrogen generation is highly desired but still remains challenging.In this work,we demonstrate that a Cu_(3)P nanoarray on copper foam(Cu_(3)P/CF)behaves as a high-performance electrocatalyst for hydrazine oxidation reaction(HzOR)in alkaline electrolytes.A full electrolytic system employing Cu_(3)P/CF as both an anode for HzOR and a cathode for hydrogen evolution reaction drives 100 mA cm^(-2)at a voltage of 0.72 V in 1.0 M KOH aqueous solution with 0.5 M hydrazine.It also demonstrates high long-term stability.展开更多
The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.H...The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.展开更多
In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace,the conventional way to deal with it is that the CaCl2 solution is prepared by tap water,and then the soluti...In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace,the conventional way to deal with it is that the CaCl2 solution is prepared by tap water,and then the solution is sprayed onto the sintered ore for improving its RDI（low temperature reduction degradation index）.The CaCl2 solution prepared by adding acid and alkaline waste water resulted from cold rolling is sprayed onto the sintered ore to improve its RDI.The values of RDI＋6.3 and RDI＋3.15 of the sintered ore which is sprayed by the CaCl2 solution with the CaCl2 concentration of 3.5%（mass percent） are increased by 17.5% and 11.63%,but the index of RDI-0.5 is decreased by 3.1% when the spraying amount of the solution is making up 0.5% of the total sintered ore sprayed in comparison with those of the sintered ore which is not sprayed by using the CaCl2 solution.Experimental results show that after the CaCl2 solutions prepared by adding the acid and alkaline waste water are sprayed on the sintered ore,RDI of the ore can be remarkably improved and therefore another way for recycling acid and alkaline waste water can be available,by which both cost for treating waste water and cost for producing a sintered ore can be decreased and environment is free of pollution by harmful substances in the waste water.展开更多
A novel 3 D bismuth-organic framework(called Bi-TBAPy) single crystal was synthesized by employing 1,3,6,8-tetrakis(p-benzoic acid)pyrene(H4TBAPy) as an organic linker. The study demonstrates that the Bi-TBAPy not onl...A novel 3 D bismuth-organic framework(called Bi-TBAPy) single crystal was synthesized by employing 1,3,6,8-tetrakis(p-benzoic acid)pyrene(H4TBAPy) as an organic linker. The study demonstrates that the Bi-TBAPy not only possesses good chemical stability and suitable band edge positions for promising photocatalytic H2 evolution, but it also exhibits a typical ligand-to-metal charge transfer for favorable charge separation. The photocatalytic H2 evolution rates on the as-obtained Bi-TBAPy with different cocatalysts modified were examined with triethanolamine as the sacrificial reagent. Based on this, the hydrogen evolution rate of 140 μmol h-1 g-1 was obtained on the optimized sample with a loading of 2 wt% Pt as a cocatalyst. To the best of our knowledge, this is the first bismuth-based metal-organic framework(MOF) that functions as an effective photocatalyst for photocatalytic water reduction. Our study not only adds a new member to the family of photocatalyst materials, but also reveals the importance of cocatalyst modification in improving photocatalytic activity of MOFs.展开更多
A new material for both magnetic coupling and electrocatalytic hydrogen generation based on a copper complex,[（HL）CuCl-CuCl（HL）]HCl 1 is prepared by the reaction of 2-（pyridylmethyl）amino-N,N-bis（2-methylene-4,...A new material for both magnetic coupling and electrocatalytic hydrogen generation based on a copper complex,[（HL）CuCl-CuCl（HL）]HCl 1 is prepared by the reaction of 2-（pyridylmethyl）amino-N,N-bis（2-methylene-4,6-difluorophenol）（H2L） and CuCl2·2H2O.In solid,complex 1 is built from two copper units（[（HL）CuCl]）,and exhibits an antiferromagnetic exchange interaction between copper（Ⅱ） ions（J=-160cm^-1）.In liquid,1 can electrocatalyze hydrogen generation both from acetic acid with a turnover frequency（TOF） of 16.3 moles of hydrogen per mole of catalyst per hour at an overpotential（OP）of 941.6 mV（in DMF）,and a neutral buffer with a TOF of 1415.6 moles of hydrogen per mole of catalyst per hour at an OP of 787.6 mV.展开更多
Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protec...Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protection. However, it still remains unclear whether the light irradiation could couple with the ultrasound to prompt the sonophotocatalytic process. Here, we selectively excited the TiO2 and Au to manipulate the electronic structures of Au/TiO2 and studied their influence in sonophotocatalytic water（H2 O） reduction. Surprisingly, no significant increase of the hydrogen（H2） production rate was observed under either the UV light irradiation or the visible light irradiation, suggesting that the change in electronic structures of Au/TiO2 does not prompt the generation of free radicals under sonication and the reaction is dominated by the recovery of active sites through ultrasound. Our findings established an indepth understanding of the origin of the enhanced catalytic activity in sonophotocatalysis.展开更多
Remote sensing and GIS applications are being widely used for various projects relating to natural resource management. Forests are very important national assets for economic, environmental protection, social and cul...Remote sensing and GIS applications are being widely used for various projects relating to natural resource management. Forests are very important national assets for economic, environmental protection, social and cultural values and should be conserved in order to realize all these benefits. Kenya’s forests are rapidly declining due to pressure from increased population, technological innovation, urbanization human development and other land uses. Mau forest is one of the major forests in Kenya that is a catchment area for many Great Rift Valley lakes within the country and faces a lot of destruction. Continued destruction of the Mau forest will cause catastrophic environmental damage, resulting in massive food crises and compromising the livelihoods of millions of Kenyans, and the possible collapse of the tourism industry. The purpose of this research was to investigate the relationship between the increasing rate of deforestation and the reduction of the volumes of water in the neighboring lakes between the years 1989 to 2010. Satellite images from Landsat-5 Thematic Mapper (TM) and Landsat-7 Enhanced Thematic Mapper (ETM+) were used for the detection of changes in the Mau forest and the dynamics of the neighboring water bodies that included lakes: Naivasha, Baringo, Nakuru, Elementaita and Bogoria. The research showed that from a period of 1989 to 2010 Mau forest has been decreasing due to deforestation and the water bodies have irregular dynamics in that, from 1989 to 2000, there was rise in the volume of water, this is attributed to the El Nino rains experienced in the country during the year 1997 and 1998. But between 2000 and 2010 the volume decreased as the forest is also decreasing. It is recommended that the government creates awareness to sensitize the public on the importance of such forests as catchment areas in Kenya.展开更多
The ability of a wet swale,constructed in an area of poor soil permeability,to manage runoff from a roadway was monitored through 27 storm events over a period of 8 months.During the monitoring period,the wet swale re...The ability of a wet swale,constructed in an area of poor soil permeability,to manage runoff from a roadway was monitored through 27 storm events over a period of 8 months.During the monitoring period,the wet swale reduced the total runoff volume by 50.4%through exfiltration and evapotranspiration.The wet swale significantly decreased the influent pollutant concentrations,and the effluent mean concentrations of total suspended solids,total phosphorus,chemical oxygen demand,ammonium,oxidized nitrogen,and total nitrogen in the effluent were 31 mg/L,0.10 mg/L,29 mg/L,0.52 mg/L,0.35 mg/L and1.28 mg/L,respectively.Pollutant loads were also substantially reduced from 70%to 85%.Plant uptake played an important role in nutrient removal in the wet swale.Approximately half of the nitrogen(53.8%)and phosphorus(51.5%)that entered the wet swale was incorporated in above-ground plants.It is shown that wet swales are useful for managing runoff from roads in areas of poor soil permeability.展开更多
In the last decades, surface drag reduction has been re-emphasized because of its practical values in engineering applications,including vehicles, aircrafts, ships, and fuel pipelines. The bionic study of drag reducti...In the last decades, surface drag reduction has been re-emphasized because of its practical values in engineering applications,including vehicles, aircrafts, ships, and fuel pipelines. The bionic study of drag reduction has been attracting scholars' attentions. Here, it was determined that the delicate microstructures on the scales of the fish Ctenopharyngodon idellus exhibit remarkable drag-reduction effect. In addition, the underlying drag-reduction mechanism was carefully investigated. First,exceptional morphologies and structures of the scales were observed and measured using a scanning electron microscope and3-dimensional(3D) microscope. Then, based on the acquired data, optimized 3D models were created. Next, the mechanism of the water-trapping effect of these structures was analyzed through numerical simulations and theoretical calculations. It was determined that there are many microcrescent units with certain distributions on its surface. In fact, these crescents are effective in generating the "water-trapping" effect and forming a fluid-lubrication film, thus reducing the skin friction drag effectively.Contrasting to a smooth surface, the dynamics finite-element analysis indicated that the maximum drag-reduction rate of a bionic surface is 3.014% at 0.66 m/s flow rate. This study can be used as a reference for an in-depth analysis on the bionic drag reduction of boats, underwater vehicles, and so forth.展开更多
In order to study the mechanism of water inrush from a concealed, confined karst cave, we established a fluid–solid coupling model of water inrush from a concealed karst cave ahead of a roadway and a strength reducti...In order to study the mechanism of water inrush from a concealed, confined karst cave, we established a fluid–solid coupling model of water inrush from a concealed karst cave ahead of a roadway and a strength reduction method in a rock pillar for preventing water inrush based on catastrophic theory. Fluid–solid coupling effects and safety margins in a rock pillar were studied. Analysis shows that rock pillar instability, exerted by disturbance stress and seepage stress, is the process of rock pillar catastrophic destabilization induced by nonlinear extension of plastic zones in the rock pillar. Seepage flow emerges in the rock pillar for preventing water inrush, accompanied by mechanical instability of the rock pillar. Taking the accident of a confined karst cave water-inrush of Qiyi Mine as an example, by studying the safety factor of the rock pillar and the relationship between karst cave water pressure and thickness of the rock pillar,it is proposed that rock pillar thickness with a safety factor equal to 1.5 is regarded as the calculated safety thickness of the rock pillar, which should be equal to the sum of the blasthole depth, blasting disturbance depth and the calculated safety thickness of the rock pillar. The cause of the karst water inrush at Qiyi Mine is that the rock pillar was so small that it did not possess a safety margin. Combining fluid–solid coupling theory, catastrophic theory and strength reduction method to study the nonlinear mechanical response of complicated rock engineering, new avenues for quantitative analysis of rock engineering stability evaluation should be forthcoming.展开更多
An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures： low-temperature roasting of vanadium-bearing titanomagnetite and water lea...An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures： low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.展开更多
In this study, fly ash obtained from a coal burning power plant was used to remove iron from coal mine drainage as well as raising the pH to acceptable limits for natural water using column chromatography. The results...In this study, fly ash obtained from a coal burning power plant was used to remove iron from coal mine drainage as well as raising the pH to acceptable limits for natural water using column chromatography. The results of this study indicate that fly ash has the ability to completely remove iron and reduce acidity of coal mine water drainage. This approach can be extended to include other contaminants such as magnesium.展开更多
基金supported financially by the National Natural Science Foundation of China(Nos.51571151,51701139,51671143,and U1601216)the China Postdoctoral Science Foundation(2019M661014)the Tianjin Natural Science Foundation(No.16JCYBJC17600)。
文摘Developing high activity and low-cost materials to produce hydrogen by the sustainable way of photoelectrochemical is key to social development.The abundance and inexpensive Cu_(2)O has been received increasing research as its suitable energy level for photocatalytic water reduction.However,the fast charge recombination rate and the sluggish catalytic kinetics are the huge challenges facing the Cu_(2)O photoreduction.Here,the highly reactive Cu_(2)O@C-MoS_(2)photocathode is constructed by depositing dual-cocatalysts of the carbon layer and MoS_(2)nanosheets on Cu_(2)O nanowires to realize efficient water reduction.An impressive carrier concentration of 6.59×10^(23)cm^(-3)is received,which is 2.78 times of the bare Cu_(2)O,resulting in remarkable enhancement in photocurrent density of 3.34 times for the Cu_(2)O@CMoS_(2)photocathode.Moreover,the applied bias photon-to-current conversion efficiency of the bare Cu_(2)O enhanced 4.5 times from 0.16%to 0.72%in the Cu_(2)O@C-MoS_(2)photocathode.The analysis shows that the Cu_(2)O as light absorber,the carbon layer as electron transfer promoter,and MoS_(2)nanosheets as catalytic sites,thus facilitating chrage separation and enhancing catalytic kinetics.This system paves a feasible strategy for designing other photoelectrodes to realize efficient charge separation and high catalytic activity.
文摘In the process of oilfield development, oilfield dewatering project has always been a big problem for oilfield developers. Because the original oilfield development technology uses a single well, the efficiency of the single well is very low, which results in the deterioration of the effect in the development process of many oilfields and the loss in oilfield development. Therefore, in order to improve the benefit of oilfield development and the effect of water flooding development, this paper makes an in-depth study on the water-stable and oil-efficient development of high-water-cut and later-stage complex fault-block oilfields.
基金supported by the National Natural Science Foundation of China(No.22405248)the Joint Fund of Science and Technology R&D Plan of Henan Province(No.232301420003).
文摘The rational design of a heterostructural photocatalysts with efficient charge separation and accelerated interfacial charge transfer holds great promise for boosting photocatalytic activity.Herein,we have developed a unique hierarchical In_(4/3)P_(2)S_(6)/TiO_(2) heterojunction with P-O interfacial bonding for photocatalytic water reduction.By integrating emerging In_(4/3)P_(2)S_(6) nanosheets through intense interfacial coupling effect,the optimized In_(4/3)P_(2)S_(6)/TiO_(2) heterostructure exhibits a remarkably enhanced photocatalytic H2 evolution activity compared to that of pristine TiO_(2).Combined experimental and theoretical results confirm that multiple interfacial bonded step-scheme(S-scheme)charge transfer pathways are established in the In_(4/3)P_(2)S_(6)/TiO_(2) photocatalyst,which synergistically promote charge separation and transfer through the robust interfacial electric field and rapid charge migration pathways formed by interfacial bonds.This study emphasizes the significance of developing novel interfacial bonded In_(4/3)P_(2)S_(6)-based S-scheme heterostructures,paving a new strategy towards enhancing photocatalytic activity for H_(2) evolution.
基金supported by the Fundamental Research Funds for the Central Universities of Chinathe Starting Research Funds of Shaanxi Normal University for Mainstay Young Scholars+2 种基金the National Environment Agency of Singapore under the Environment Technology Research Programme(ETRP)through Project No.ETRP 1002 103Singapore National Research Foundation(NRF)through the Singapore-Berkeley Research Initiative for Sustainable Energy(SinBeRISE)Cambridge Centre for Carbon Reduction in Chemical Technology(C4T)CREATE Programmes
文摘Photocatalytic water splitting and carbon dioxide reduction provide us clean and sustainable energy resources. The carbon dioxide reduction is also the redemption of the greenhouse effect. MoS/TiOphotocatalysts based on TiOnanoplates have been synthesized via a hydrothermal acidification route for water and carbon dioxide reduction reactions. This facile approach generates well dispersed Mo S3 with low crystallinity on the surface of TiOnanoplates. The as-synthesized MoS/TiOphotocatalyst showed considerable activity for both water reduction and carbon dioxide reduction. The thermal treatment effects of TiO, the loading percentage of MoSand the crystalline phase of TiOhave been investigated towards the photocatalytic performance. TiOnanoplate synthesized through hydrothermal reaction with the presence of HF acid is an ideal semiconductor material for the loading of MoSfor photocatalytic water and carbon dioxide reduction simultaneously in EDTA sacrificial solution.
文摘Drinking water loss or Non-Revenue Water (NRW) threatens the financial viability of water utilities and sustainable natural water resource management. However, little attention has been paid to quantitative assessment of the spatial distribution of water losses in Rwanda. Therefore, this study focused on the magnitude of water losses, the associated environmental and socio-economic consequences, as well as the potential benefits from water loss reduction in Rwanda. Based on water usage records from the Water and Sanitation Corporation (WASAC) of Rwanda, NRW was calculated for 15 WASAC branches and Provinces, from July 2013 to June 2014, by using the International Water Association (IWA) standard water balance approach. The results highlight an annual NRW of 16,502,198 or 41% of the total water produced, inducing a revenue loss of US$ 8,713,156. In 14 of the 15 WASAC water branches and all Rwandan provinces, the NRW ratios exceed the NRW threshold (10%) recommended by the American Water Works Association (AWWA). Because of the lost revenue, the water facilities may not expand quickly enough to meet the demands of the rapidly growing population. The suggested 50% reduction in NRW would provide additional 8,251,100 m<sup>3</sup> of treated water yearly, enough to serve extra 41,925 households or irrigate 661 ha of cropland and save US$ 4,356,579, which would reduce the financial gap in Rwanda’s National Water Improvement Project by more than 24%.
基金National Natural Science Foundation of China(Grant No.51972233)Natural Science Foundation of Shanghai(Grant No.19ZR1459200)+1 种基金Shanghai Science and Technology Commission(Grant No.14DZ2261100)he Fundamental Research Funds for the Central Universities.
文摘La/Zr co-doped SrTaO_(2)N has been investigated as visible-light-active photocatalysts for water reduction.Unlike previous aliovalent doping that leads to a decrease in light absorption,La/Zr co-doping largely preserves the visible light absorption of SrTaO_(2)N.More importantly,the La/Zr co-doping not only helps to improve surface hydrophilicity and reduce particle sizes but also effectively inhibits defect formation(e.g.Ta^(4+))in SrTaO_(2)N.These modifications are responsible for significant enhancements in photocatalytic H_(2)production.AQE as high as 0.84%was achieved at 420±20 nm for Sr_(0.4)La_(0.6)Ta_(0.4)Zr_(0.6)O_(2)N(x=0.6),which also showed good durability and stability.Further analysis suggests that La/Zr co-doping negatively shifts the conduction band edge positions of SrTaO_(2)N and contributes to better charge separation conditions.
基金the UGC-BSR-Mid-Career Award Project(Project No.19-232/2019(BSR))IoE,University of Hyderabad(Project No.RC1-20-007)for financial support.
文摘Grafting a WVI–(OH)_(2) functionality on the surface of polyoxometalates (POMs) makes the concerned POM compounds,Na_(6)[{CoⅡ(H_(2)O)_(3)}_(2){WVI(OH)_(2)}_(2){(BiⅢWVI_(9)O_(3)_(3))_(2)}]·8H_(2)O (1) and Na_(4)(Himi)_(2)[{MnⅡ(H_(2)O)_(3)}_(2){WVI(OH)_(2)}_(2){(BiⅢWVI_(9)O_(3)_(3))_(2)}]·28H_(2)O (2) prominent heterogeneous electrocatalysts for water reduction to molecular hydrogen. We have identified that the WVI–(OH)_(2) functionality acts as the active site for electrocatalytic hydrogen evolution reaction (HER). The chances of in situ generation and participation of secondary species (metal nanoparticles etc.) in the present electrocatalysis have been eliminated by performing controlled experiments. The electrocatalysts 1 and 2 are stable enough towards HER up to 1000 cycles of cyclic voltammetric measurement and 10 hours chronoamperometry. The relevant turnover frequencies of 1 and 2 are 0.593 s^(-1) and 0.634 s^(-1) respectively exhibiting high efficiency towards electrocatalytic HER. This work has potential to generalize that POMs having M–OH functionality attached on its cluster surface would function as catalysts for HER.
文摘Herein,we disclosed the g-C_(3)N_(4)/LaFeO_(3) nanocomposite photocatalyst,a mediator-free direct Z-scheme photocatalytic system,prepared using a mechanical mixing method with reliable interfacial interactions. The nanocomposite formation was determined by X-ray diffraction (XRD),transmission electron microscopy (TEM),and X-ray photoelectron spectroscopy (XPS). The optical properties of the nanohybrids were also characterized using UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) spectroscopy. The results clearly indicated that the g-C_(3)N_(4)/LaFeO_(3) nanocomposite was effectively fabricated,with reliable interfacial interactions and a good heterojunction interaction between g-C_(3)N_(4) and LaFeO_(3),which can considerably enhance the photocatalytic activity as compared to pristine g-C_(3)N_(4) and LaFeO_(3). The high HER (1152 μmol h^(−1) g^(−1)) was also confirmed by the PL spectra,Mott–Schottky plot,electrochemical impedance spectroscopy (EIS),and solid–solid interfacial interactions.
基金National Natural Science Foundation of China(21575137)。
文摘Energy-efficient electrolytic hydrogen generation is highly desired but still remains challenging.In this work,we demonstrate that a Cu_(3)P nanoarray on copper foam(Cu_(3)P/CF)behaves as a high-performance electrocatalyst for hydrazine oxidation reaction(HzOR)in alkaline electrolytes.A full electrolytic system employing Cu_(3)P/CF as both an anode for HzOR and a cathode for hydrogen evolution reaction drives 100 mA cm^(-2)at a voltage of 0.72 V in 1.0 M KOH aqueous solution with 0.5 M hydrazine.It also demonstrates high long-term stability.
基金financial support of the National Natural Science Foundation of China(U21A20218 and 32101857)the‘Double First-Class’Key Scientific Research Project of Education Department in Gansu Province,China(GSSYLXM-02)+1 种基金the Fuxi Young Talents Fund of Gansu Agricultural University,China(Gaufx03Y10)the“Innovation Star”Program of Graduate Students in 2023 of Gansu Province,China(2023CXZX681)。
文摘The development of modern agriculture requires the reduction of water and chemical N fertilizer inputs.Increasing the planting density can maintain higher yields,but also consumes more of these restrictive resources.However,whether an increased maize density can compensate for the negative effects of reduced water and N supply on grain yield and N uptake in the arid irrigated areas remains unknown.This study is part of a long-term positioning trial that started in 2016.A split-split plot field experiment of maize was implemented in the arid irrigated area of northwestern China in 2020 to 2021.The treatments included two irrigation levels:local conventional irrigation reduced by 20%(W1,3,240 m^(3)ha^(-1))and local conventional irrigation(W2,4,050 m^(3)ha^(-1));two N application rates:local conventional N reduced by 25%(N1,270 kg ha^(-1))and local conventional N(360 kg ha^(-1));and three planting densities:local conventional density(D1,75,000 plants ha^(-1)),density increased by 30%(D2,97,500 plants ha-1),and density increased by 60%(D3,120,000 plants ha^(-1)).Our results showed that the grain yield and aboveground N accumulation of maize were lower under the reduced water and N inputs,but increasing the maize density by 30% can compensate for the reductions of grain yield and aboveground N accumulation caused by the reduced water and N supply.When water was reduced while the N application rate remained unchanged,increasing the planting density by 30% enhanced grain yield by 13.9% and aboveground N accumulation by 15.3%.Under reduced water and N inputs,increasing the maize density by 30% enhanced N uptake efficiency and N partial factor productivity,and it also compensated for the N harvest index and N metabolic related enzyme activities.Compared with W2N2D1,the N uptake efficiency and N partial factor productivity increased by 28.6 and 17.6%under W1N1D2.W1N2D2 had 8.4% higher N uptake efficiency and 13.9% higher N partial factor productivity than W2N2D1.W1N2D2 improved urease activity and nitrate reductase activity by 5.4% at the R2(blister)stage and 19.6% at the V6(6th leaf)stage,and increased net income and the benefit:cost ratio by 22.1 and 16.7%,respectively.W1N1D2 and W1N2D2 reduced the nitrate nitrogen and ammoniacal nitrogen contents at the R6 stage in the 40-100 cm soil layer,compared with W2N2D1.In summary,increasing the planting density by 30% can compensate for the loss of grain yield and aboveground N accumulation under reduced water and N inputs.Meanwhile,increasing the maize density by 30% improved grain yield and aboveground N accumulation when water was reduced by 20% while the N application rate remained constant in arid irrigation areas.
基金Item Sponsored by National Natural Science Foundation of China(51274120)
文摘In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace,the conventional way to deal with it is that the CaCl2 solution is prepared by tap water,and then the solution is sprayed onto the sintered ore for improving its RDI（low temperature reduction degradation index）.The CaCl2 solution prepared by adding acid and alkaline waste water resulted from cold rolling is sprayed onto the sintered ore to improve its RDI.The values of RDI＋6.3 and RDI＋3.15 of the sintered ore which is sprayed by the CaCl2 solution with the CaCl2 concentration of 3.5%（mass percent） are increased by 17.5% and 11.63%,but the index of RDI-0.5 is decreased by 3.1% when the spraying amount of the solution is making up 0.5% of the total sintered ore sprayed in comparison with those of the sintered ore which is not sprayed by using the CaCl2 solution.Experimental results show that after the CaCl2 solutions prepared by adding the acid and alkaline waste water are sprayed on the sintered ore,RDI of the ore can be remarkably improved and therefore another way for recycling acid and alkaline waste water can be available,by which both cost for treating waste water and cost for producing a sintered ore can be decreased and environment is free of pollution by harmful substances in the waste water.
基金supported by the National Natural Science Foundation of China(21633009,21522306,21633010)DICP&QIBEBT(UN201805)the Dalian Science Foundation for Distinguished Young Scholars(2017RJ02)~~
文摘A novel 3 D bismuth-organic framework(called Bi-TBAPy) single crystal was synthesized by employing 1,3,6,8-tetrakis(p-benzoic acid)pyrene(H4TBAPy) as an organic linker. The study demonstrates that the Bi-TBAPy not only possesses good chemical stability and suitable band edge positions for promising photocatalytic H2 evolution, but it also exhibits a typical ligand-to-metal charge transfer for favorable charge separation. The photocatalytic H2 evolution rates on the as-obtained Bi-TBAPy with different cocatalysts modified were examined with triethanolamine as the sacrificial reagent. Based on this, the hydrogen evolution rate of 140 μmol h-1 g-1 was obtained on the optimized sample with a loading of 2 wt% Pt as a cocatalyst. To the best of our knowledge, this is the first bismuth-based metal-organic framework(MOF) that functions as an effective photocatalyst for photocatalytic water reduction. Our study not only adds a new member to the family of photocatalyst materials, but also reveals the importance of cocatalyst modification in improving photocatalytic activity of MOFs.
基金supported by the National Natural Science Foundation of China (Nos. 20971045, 21271073)
文摘A new material for both magnetic coupling and electrocatalytic hydrogen generation based on a copper complex,[（HL）CuCl-CuCl（HL）]HCl 1 is prepared by the reaction of 2-（pyridylmethyl）amino-N,N-bis（2-methylene-4,6-difluorophenol）（H2L） and CuCl2·2H2O.In solid,complex 1 is built from two copper units（[（HL）CuCl]）,and exhibits an antiferromagnetic exchange interaction between copper（Ⅱ） ions（J=-160cm^-1）.In liquid,1 can electrocatalyze hydrogen generation both from acetic acid with a turnover frequency（TOF） of 16.3 moles of hydrogen per mole of catalyst per hour at an overpotential（OP）of 941.6 mV（in DMF）,and a neutral buffer with a TOF of 1415.6 moles of hydrogen per mole of catalyst per hour at an OP of 787.6 mV.
基金supported by the National Science Foundation 9(NSF, No. DMR-1352328)supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, under Contract No. DE-SC0012704
文摘Sonophotocatalysis combines ultrasonic and light irradiations to drastically boost the chemical reaction rate and has attracted many interests for its potential applications in the environmental remediation and protection. However, it still remains unclear whether the light irradiation could couple with the ultrasound to prompt the sonophotocatalytic process. Here, we selectively excited the TiO2 and Au to manipulate the electronic structures of Au/TiO2 and studied their influence in sonophotocatalytic water（H2 O） reduction. Surprisingly, no significant increase of the hydrogen（H2） production rate was observed under either the UV light irradiation or the visible light irradiation, suggesting that the change in electronic structures of Au/TiO2 does not prompt the generation of free radicals under sonication and the reaction is dominated by the recovery of active sites through ultrasound. Our findings established an indepth understanding of the origin of the enhanced catalytic activity in sonophotocatalysis.
文摘Remote sensing and GIS applications are being widely used for various projects relating to natural resource management. Forests are very important national assets for economic, environmental protection, social and cultural values and should be conserved in order to realize all these benefits. Kenya’s forests are rapidly declining due to pressure from increased population, technological innovation, urbanization human development and other land uses. Mau forest is one of the major forests in Kenya that is a catchment area for many Great Rift Valley lakes within the country and faces a lot of destruction. Continued destruction of the Mau forest will cause catastrophic environmental damage, resulting in massive food crises and compromising the livelihoods of millions of Kenyans, and the possible collapse of the tourism industry. The purpose of this research was to investigate the relationship between the increasing rate of deforestation and the reduction of the volumes of water in the neighboring lakes between the years 1989 to 2010. Satellite images from Landsat-5 Thematic Mapper (TM) and Landsat-7 Enhanced Thematic Mapper (ETM+) were used for the detection of changes in the Mau forest and the dynamics of the neighboring water bodies that included lakes: Naivasha, Baringo, Nakuru, Elementaita and Bogoria. The research showed that from a period of 1989 to 2010 Mau forest has been decreasing due to deforestation and the water bodies have irregular dynamics in that, from 1989 to 2000, there was rise in the volume of water, this is attributed to the El Nino rains experienced in the country during the year 1997 and 1998. But between 2000 and 2010 the volume decreased as the forest is also decreasing. It is recommended that the government creates awareness to sensitize the public on the importance of such forests as catchment areas in Kenya.
基金Project(2011ZX07303-002) supported by National Water Pollution Control and Management Technology Major Projects,China
文摘The ability of a wet swale,constructed in an area of poor soil permeability,to manage runoff from a roadway was monitored through 27 storm events over a period of 8 months.During the monitoring period,the wet swale reduced the total runoff volume by 50.4%through exfiltration and evapotranspiration.The wet swale significantly decreased the influent pollutant concentrations,and the effluent mean concentrations of total suspended solids,total phosphorus,chemical oxygen demand,ammonium,oxidized nitrogen,and total nitrogen in the effluent were 31 mg/L,0.10 mg/L,29 mg/L,0.52 mg/L,0.35 mg/L and1.28 mg/L,respectively.Pollutant loads were also substantially reduced from 70%to 85%.Plant uptake played an important role in nutrient removal in the wet swale.Approximately half of the nitrogen(53.8%)and phosphorus(51.5%)that entered the wet swale was incorporated in above-ground plants.It is shown that wet swales are useful for managing runoff from roads in areas of poor soil permeability.
基金supported by the National Natural Science Foundation of China(Grant Nos.51305282,51505183&51325501)Program for Excellent Talents of Liaoning Provincial Committee of Education(Grant No.LJQ2014071)
文摘In the last decades, surface drag reduction has been re-emphasized because of its practical values in engineering applications,including vehicles, aircrafts, ships, and fuel pipelines. The bionic study of drag reduction has been attracting scholars' attentions. Here, it was determined that the delicate microstructures on the scales of the fish Ctenopharyngodon idellus exhibit remarkable drag-reduction effect. In addition, the underlying drag-reduction mechanism was carefully investigated. First,exceptional morphologies and structures of the scales were observed and measured using a scanning electron microscope and3-dimensional(3D) microscope. Then, based on the acquired data, optimized 3D models were created. Next, the mechanism of the water-trapping effect of these structures was analyzed through numerical simulations and theoretical calculations. It was determined that there are many microcrescent units with certain distributions on its surface. In fact, these crescents are effective in generating the "water-trapping" effect and forming a fluid-lubrication film, thus reducing the skin friction drag effectively.Contrasting to a smooth surface, the dynamics finite-element analysis indicated that the maximum drag-reduction rate of a bionic surface is 3.014% at 0.66 m/s flow rate. This study can be used as a reference for an in-depth analysis on the bionic drag reduction of boats, underwater vehicles, and so forth.
基金Financial supports for this work, provided by the National Natural Science Foundation of China (No. 51274097)the Scientific Research Fund of Hunan Provincial Education Department of China (No. 13A020)the Open Projects of State Key Laboratory of Coal Resources and Safe Mining, CUMT (No. 13KF03)
文摘In order to study the mechanism of water inrush from a concealed, confined karst cave, we established a fluid–solid coupling model of water inrush from a concealed karst cave ahead of a roadway and a strength reduction method in a rock pillar for preventing water inrush based on catastrophic theory. Fluid–solid coupling effects and safety margins in a rock pillar were studied. Analysis shows that rock pillar instability, exerted by disturbance stress and seepage stress, is the process of rock pillar catastrophic destabilization induced by nonlinear extension of plastic zones in the rock pillar. Seepage flow emerges in the rock pillar for preventing water inrush, accompanied by mechanical instability of the rock pillar. Taking the accident of a confined karst cave water-inrush of Qiyi Mine as an example, by studying the safety factor of the rock pillar and the relationship between karst cave water pressure and thickness of the rock pillar,it is proposed that rock pillar thickness with a safety factor equal to 1.5 is regarded as the calculated safety thickness of the rock pillar, which should be equal to the sum of the blasthole depth, blasting disturbance depth and the calculated safety thickness of the rock pillar. The cause of the karst water inrush at Qiyi Mine is that the rock pillar was so small that it did not possess a safety margin. Combining fluid–solid coupling theory, catastrophic theory and strength reduction method to study the nonlinear mechanical response of complicated rock engineering, new avenues for quantitative analysis of rock engineering stability evaluation should be forthcoming.
基金financially supported by the National Basic Research Program of China(Nos.2013CB632601 and 2013CB632604)the National Science Foundation for Distinguished Young Scholars of China(Nos.51125018 and 51504230)+3 种基金the Key Research Program of the Chinese Academy of Sciences(No.KGZD-EW-201-2)the National Natural Science Foundation of China(Nos.51374191,21106167,2160624,and 51104139)the Financial Grant from the China Postdoctoral Science Foundation(Nos.2012M510552 and 2013T60175)the Nonprofit Industry Research Subject of Environmental Projection(No.201509053)
文摘An innovative method for recovering valuable elements from vanadium-bearing titanomagnetite is proposed. This method involves two procedures： low-temperature roasting of vanadium-bearing titanomagnetite and water leaching of roasting slag. During the roasting process, the reduction of iron oxides to metallic iron, the sodium oxidation of vanadium oxides to water-soluble sodium vanadate, and the smelting separation of metallic iron and slag were accomplished simultaneously. Optimal roasting conditions for iron/slag separation were achieved with a mixture thickness of 42.5 mm, a roasting temperature of 1200°C, a residence time of 2 h, a molar ratio of C/O of 1.7, and a sodium carbonate addition of 70 wt%, as well as with the use of anthracite as a reductant. Under the optimal conditions, 93.67% iron from the raw ore was recovered in the form of iron nugget with 95.44% iron grade. After a water leaching process, 85.61% of the vanadium from the roasting slag was leached, confirming the sodium oxidation of most of the vanadium oxides to water-soluble sodium vanadate during the roasting process. The total recoveries of iron, vanadium, and titanium were 93.67%, 72.68%, and 99.72%, respectively.
文摘In this study, fly ash obtained from a coal burning power plant was used to remove iron from coal mine drainage as well as raising the pH to acceptable limits for natural water using column chromatography. The results of this study indicate that fly ash has the ability to completely remove iron and reduce acidity of coal mine water drainage. This approach can be extended to include other contaminants such as magnesium.
